/*
 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package org.eclipse.imagen.iterator;

/**
 * An iterator for traversing a read-only image using arbitrary up-down and left-right moves. This will generally be
 * somewhat slower than a corresponding instance of RectIter, since it must perform bounds checks against the top and
 * left edges of tiles in addition to their bottom and right edges.
 *
 * <p>The iterator is initialized with a particular rectangle as its bounds, which it is illegal to exceed. This
 * initialization takes place in a factory method and is not a part of the iterator interface itself. Once initialized,
 * the iterator may be reset to its initial state by means of the startLine(), startPixels(), and startBands() methods.
 * As with RectIter, its position may be advanced using the nextLine(), jumpLines(), nextPixel(), jumpPixels(), and
 * nextBand() methods.
 *
 * <p>In addition, prevLine(), prevPixel(), and prevBand() methods exist to move in the upwards and leftwards directions
 * and to access smaller band indices. The iterator may be set to the far edges of the bounding rectangle by means of
 * the endLines(), endPixels(), and endBands() methods.
 *
 * <p>The iterator's position may be tested against the bounding rectangle by means of the finishedLines(),
 * finishedPixels(), and finishedBands() methods, as well as the hybrid methods nextLineDone(), prevLineDone(),
 * nextPixelDone(), prevPixelDone(), nextBandDone(), and prevBandDone().
 *
 * <p>The getSample(), getSampleFloat(), and getSampleDouble() methods are provided to allow read-only access to the
 * source data. The various source bands may also be accessed in random fashion using the variants that accept a band
 * index. The getPixel() methods allow retrieval of all bands simultaneously.
 *
 * <p>An instance of RookIter may be obtained by means of the RookIterFactory.create() method, which returns an opaque
 * object implementing this interface.
 *
 * @see RectIter
 * @see RookIterFactory
 */
public interface RookIter extends RectIter {

    /**
     * Sets the iterator to the previous line of the image. The pixel and band offsets are unchanged. If the iterator
     * passes the top line of the rectangle, calls to get() methods are not valid.
     */
    public void prevLine();

    /**
     * Sets the iterator to the previous line in the image, and returns true if the top row of the bounding rectangle
     * has been passed.
     */
    public boolean prevLineDone();

    /** Sets the iterator to the last line of its bounding rectangle. The pixel and band offsets are unchanged. */
    void endLines();

    /**
     * Sets the iterator to the previous pixel in the image (that is, move leftward). The line and band offsets are
     * unchanged.
     */
    public void prevPixel();

    /**
     * Sets the iterator to the previous pixel in the image (that is, move leftward). Returns true if the left edge of
     * the bounding rectangle has been passed. The line and band offsets are unchanged.
     */
    public boolean prevPixelDone();

    /** Sets the iterator to the rightmost pixel of its bounding rectangle. The line and band offsets are unchanged. */
    void endPixels();

    /** Sets the iterator to the previous band in the image. The pixel column and line are unchanged. */
    void prevBand();

    /**
     * Sets the iterator to the previous band in the image, and returns true if the min band has been exceeded. The
     * pixel column and line are unchanged.
     */
    boolean prevBandDone();

    /** Sets the iterator to the last band of the image. The pixel column and line are unchanged. */
    void endBands();
}
